1. Field of the Invention
The present invention relates to preparation of coaxial cables and, more specifically, to cutting tools for removing portions of a coaxial cable prior to the attachment of a connector.
2. Description of the Related Art
FIG. 1A schematically shows a representative unprepared coaxial cable 102 including two conductors, i.e., a wire core 104 and a shielding mesh 108. Cable 102 also has (i) an inner insulation layer 106 that electrically insulates core 104 from mesh 108 and (ii) an outer protective jacket 110 that encloses core 104, insulation layer 106, and mesh 108.
FIG. 1B schematically shows cable 102 (labeled 102xe2x80x2) after it has been appropriately prepared for the attachment of an electrical connector. More specifically, cable 102xe2x80x2 has a xe2x80x9csteppedxe2x80x9d cable end 112, which exposes core 104 and mesh 108 to meet the requirements for the selected type of connector. In particular, inner insulation layer 106, shielding mesh 108, and outer jacket 110 are removed from a first predetermined length of cable 102 to expose core 104, and outer jacket 110 is removed from a second predetermined length of cable 102 to expose shielding mesh 108. As a result, the connector can be properly attached to stepped cable end 112 of cable 102xe2x80x2 as known in the art.
Preparing stepped cable end 112 may present significant problems for cable 102 having a relatively large diameter, e.g., over 1 inch. In particular, specialized tools developed for preparation of coaxial cables having a relatively small diameter are not sufficiently robust to perform similar operations on larger cables. As a result, technical personnel are often forced to use non-specialized tools such as hack saws and knives, which is inefficient in terms of time and often results in a poor-quality stepped cable end.
The problems in the prior art are addressed, in accordance with the principles of the invention, by a coaxial cable cutting tool that can be used to form a stepped cable end prior to the attachment of an electrical connector to a coaxial cable. In one embodiment, the cutting tool has a blade assembly supported inside a housing on a pair of cams. A coaxial cable is inserted into the cutting tool and the housing is rotated about the cable to push the blade assembly along spiral tracks in the cams. According to one embodiment of the invention, the blade assembly has three blades, each blade sized and positioned to make a cut of the corresponding appropriate depth in the coaxial cable thereby forming the desired stepped cable end. Cutting tools of the invention may be adapted for preparation of large-diameter (e.g., over 1 inch) coaxial cables.
According to one embodiment, the present invention is a tool designed to form a stepped cable end in a coaxial cable, comprising: a blade assembly supported in a housing by a first cam and a second cam, wherein: each cam is rotatably connected to the housing and has a spiral track; the blade assembly is adapted to move along the spiral tracks; and the motion of the blade assembly forms one or more cuts in the coaxial cable, said cuts corresponding to the stepped cable end.
According to another embodiment, the present invention is a method of forming a stepped cable end, comprising rotating a blade assembly about a coaxial cable, wherein: the blade assembly is supported in a housing by a first cam and a second cam; each cam is rotatably connected to the housing and has a spiral track; the blade assembly is adapted to move along the spiral tracks; and the motion of the blade assembly forms one or more cuts in the coaxial cable, said cuts corresponding to the stepped cable end.